The present invention relates to a plunger lift type oil and gas well, wherein the natural gas/oil pressures from the earth propel the gas/oil to the surface. A metal ball replaces the traditional elongated plunger, wherein the metal ball acts as the interface between the lifting gas in the well""s tubing and the liquid column which is lifted upward to harvest.
Plunger lift wells are known in the art. They can replace a pumping unit and the associated machinery with a cyclic harvesting system which uses the earth""s natural gasses in the deposit layer to push upward a column of oil. The well""s tubing may be a mile deep in the earth. The goal of the system is to harvest only one column of liquid at a time. Then a plunger which has risen with that harvested column shuts off the well. The plunger slowly sinks to the bottom of the tubing, thereby allowing the earth""s pressure, (250-2000 psi) at the well bottom to replenish. This cycle repeats itself perhaps twice a day. The plunger triggers an arrival sensor at the top of its journey up the well tubing. The arrival sensor shuts off the well head to let the plunger sink to the bottom of the well again. A clearance of thousandths of an inch exists between the plunger and the tubing to enable the liquid under the plunger to pass by the sinking plunger.
Current plungers are relatively expensive multi-part assemblies. See Production Control Services, Inc. at www.pcsplungerlift.com, for a product line description. It is known that elongate plungers wear out the (over a mile long) well tubing, thus causing costly downtime and tubing repairs.
The present invention replaces the elongate plunger assembly with a metal ball having approximately the same diameter as the elongate plunger. Benefits of the present invention include a lower cost and less friction and wear against the inside of the well tube. A ball has less contact area sliding in a pipe than an elongate plunger sliding in the pipe.
The main aspect of the present invention is to provide a ball to replace an elongate plunger in a plunger lift type well.
Another aspect of the present invention is to provide a ball fishing apparatus to retrieve the ball at the bottom of the well tubing during maintenance.
Other aspects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
The general advantages of a plunger lift well are:
Low maintenance cost. On average less than $1000 per year.
Increases the well""s own lifting efficiency.
Easy installation when seating nipple or tubing stop is in the hole.
Reduces paraffin or hot oil expense.
No external energy (expense) required.
Produces most wells to depletion.
Replaces pumping units on most gas wells.
Slows well decline.
Extends the lift of the well.
In operation a plunger is removed from a plunger lift type well during a closed part of the plumping cycle. A stainless steel ball having the same diameter as the plunger is put in the well tubing. The ball falls (in perhaps one hour to half a day) to the well bottom. The well head is opened to allow the harvest of one column of oil. When the ball trips the arrival sensor (just like the plunger did), the well head is shut off. The only other change to the plunger lift system to accommodate the ball is to add a safety bar(s) on the inside of the well head piping to preclude the passage of the ball beyond the confines of the vertical tubing. New systems may be designed with the ball, and may provide a wider inside diameter at the well bottom (based on projections) which would increase the throughput of the well.